1. Field of the Invention
The present invention relates to a vaporization electrode.
2. Description of Related Art
Electrodes of the kind illustratively disclosed in DE 295 21 028 U1 are used for vaporization in the presence of water, for instance in the bladder. The functional surface of the electrode is moved against a tissue surface. The high frequency (hf) of the electrode causes the tissue to heat to carbonization.
In earlier techniques, when working in a poor electrically conducting liquid, the hf current loading the electrode was constrained, upon its making contact with the tissue, to pass through latter until reaching an external neutral electrode. The tissue was heated by the current.
More modern techniques are carried out in liquids that conduct electricity well. The current from the vaporization electrode's functional surface passes through the liquid to a nearby return electrode. The tissue is heated by a plasma building up above the functional surface.
However, problems are incurred because the plasma may be formed at all electrically conducting vaporization electrode areas. In other words, the plasma is formed not only at the functional surface, but also elsewhere. Therefore, the feed wire is protected by an insulating sheath to preclude spurious plasma formation.
On the other hand, the insulating sheath is delicate. Because of its complex assembly, it is made at least of plastic in the feed conductor's end zone near the electrode. However, this plastic is thermally susceptible. Plasma forming in the vicinity of the insulating sheath destroys it.
Accordingly, the objective of the present invention is to preclude destruction by plasma of a vaporization electrode of the above cited kind.